package com.yang;

import java.util.ArrayList;
import java.util.List;

public class Work1 {
    public static void main(String[] args) {
    int[] arr={1,2,3};
     System.out.println(result(arr));
    }
    public static String result(int[] arr){
        List<Integer> list= new ArrayList();
        for (int i=0;i<arr.length;i++){
            if(list.contains(arr[i])){
                return "NO";
            }
            else {
                list.add(arr[i]);
            }
        }
        return "YES";
    }
}
